Modern wind turbine rotor blades are built from fiber-reinforced plastics such as glass fiber reinforced epoxy plastic or carbon fiber reinforced epoxy plastic. A rotor blade typically comprises an airfoil having a rounded leading edge and a sharp trailing edge. The rotor blade is connected with its blade root to a hub of the wind turbine. Such a rotor blade can be produced in the so-called vacuum assisted resin transfer molding technique, also named VARTM. A number of e.g. glass fiber fabrics are placed as a stack in a mold. The mold is closed, and evacuated to low pressure by means of a vacuum pump. Thereafter a liquid resin is infused into the laminate stack in the mold cavity and left to cure. After cure, the wind turbine blade can be taken out of the mold and then be finished.
As the need for non-fossil electricity production is rapidly growing, wind turbine blades grow dramatically in size. Blades exceeding 50 meter length poses an extreme challenge to road transportation. Thus, the need for splitting blades in two or more parts during transportation to the erection site seems to be necessary. In the near future blades exceeding 100 meter will be built and these blades are nearly impossible to transport in many public road systems. US 2010/0158694 A1 describes a rotor blade comprising a plurality of blade modules being connected to each other with fasteners.